[SCEV] Revert bailout added in r75511.

Summary:
With the introduction of MarkPendingLoopPredicates in r157092, I don't
think the bailout is needed anymore.

Reviewers: atrick, nicholas

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D8624

llvm-svn: 233296

1 files changed, 11 insertions, 12 deletions

diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index fdfe5cbd498..4e713fb1218 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -6793,15 +6793,6 @@ bool ScalarEvolution::isImpliedCond(ICmpInst::Predicate Pred,
   ICmpInst *ICI = dyn_cast<ICmpInst>(FoundCondValue);
   if (!ICI) return false;
 
-  // Bail if the ICmp's operands' types are wider than the needed type
-  // before attempting to call getSCEV on them. This avoids infinite
-  // recursion, since the analysis of widening casts can require loop
-  // exit condition information for overflow checking, which would
-  // lead back here.
-  if (getTypeSizeInBits(LHS->getType()) <
-      getTypeSizeInBits(ICI->getOperand(0)->getType()))
-    return false;
-
   // Now that we found a conditional branch that dominates the loop or controls
   // the loop latch. Check to see if it is the comparison we are looking for.
   ICmpInst::Predicate FoundPred;
@@ -6813,9 +6804,17 @@ bool ScalarEvolution::isImpliedCond(ICmpInst::Predicate Pred,
   const SCEV *FoundLHS = getSCEV(ICI->getOperand(0));
   const SCEV *FoundRHS = getSCEV(ICI->getOperand(1));
 
-  // Balance the types. The case where FoundLHS' type is wider than
-  // LHS' type is checked for above.
-  if (getTypeSizeInBits(LHS->getType()) >
+  // Balance the types.
+  if (getTypeSizeInBits(LHS->getType()) <
+      getTypeSizeInBits(FoundLHS->getType())) {
+    if (CmpInst::isSigned(Pred)) {
+      LHS = getSignExtendExpr(LHS, FoundLHS->getType());
+      RHS = getSignExtendExpr(RHS, FoundLHS->getType());
+    } else {
+      LHS = getZeroExtendExpr(LHS, FoundLHS->getType());
+      RHS = getZeroExtendExpr(RHS, FoundLHS->getType());
+    }
+  } else if (getTypeSizeInBits(LHS->getType()) >
       getTypeSizeInBits(FoundLHS->getType())) {
     if (CmpInst::isSigned(FoundPred)) {
       FoundLHS = getSignExtendExpr(FoundLHS, LHS->getType());